Depression is a prevalent neuropsychiatric illness with devastating medical and socio-economic consequences. Although many patients respond to current treatments, up to 25% do not respond, or have substantial side effects. New treatments are desperately needed. This application for Mentored Clinical Scientist Development Award responds to the NIMH Strategic Plan for Mood Disorder Research recommendation to develop experts in translational research. Animal models of depression like the Forced Swim Test (FST) predict human antidepressant activity. Almost all antidepressant drugs and electro-convulsive therapy used in daily clinical practice have been validated with the FST. Deep brain stimulation (DBS) is an invasive technique that could potentially play a role in targeted antidepressant treatment delivery in medication resistant patients. DBS is postulated to inhibit dysfunctional brain systems implicated in maladaptive responses to stress and linked to the pathophysiology of depression. At the moment, enthusiasm for applying DBS in depressed populations is limited by the ethical concern that since these dysfunctional depression networks are not fully worked out in humans, it is unclear where to implant a DBS electrode in man. That is, there is inadequate basic animal research at the moment to support the choice of a targeted area. This proposal is designed to fill several of these gaps. It offers to train the candidate to become an expert in translation depression research, with training in DBS, predictors of antidepressant response in rodents, immunocytochemistry of immediate early gene expression and advanced research methodology. The scientific study within this training award is designed to teach the candidate new methods and approaches, while also answering important questions in this area. Sprague-Dawley rats will be divided into 12 groups in a parallel double-blind design and implanted with bilateral DBS to either the centro-medial amygdala (CMA), dorsal raphe (DR), or anterior cingulate cortex (ACC). Each group will receive an intraperitoneal injection of fluoxetine (FLX) (an effective antidepressant drug) or saline (SAL) and be stimulated with either active DBS (DBS) or sham DBS (NoSTM). Rats will be tested once (FLX/DBS, FLX/NoSTM, SAL/DBS, SAL/NoSTM). FST immobility time will serve as a primary outcome measure. 30 minutes from FST start, the brains will be stained for c-fos using immunocychemistry method. C-fos profiles will serve as exploratory measures of antidepressant response and regional circuitry. This K08 expands on and complements the candidate's special expertise in clinical research of electrical neuromodulation applied to mood disorders. The knowledge from this 5-year career development award will position him to better guide future therapeutic applications of DBS. Future work will bridge between validating these findings in more comprehensive models of depression and clinical investigations of the DBS antidepressant effect in patients with treatment resistant depression.